Control system



Nov. 12, 1940- A. J. A. PETERSON ET AL 2,221,604

CONTROL SYSTEM Filed Jan. 24, 1940 169- 5 Hy]. l2

WITNESSES: 44 {J0 Ma/M INVENTORS AZ/ieJJAfifmar,

a ATTORZgY Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE CONTROL SYSTEM Application January 24, 1940, Serial No. 315,360

19 Claims.

Our invention relates, generally, to control systems, and, more particularly, to systems providing an electrical interlock between associated circuit breakers or other relatively movable devices.

In the operation of synchronous motors and some other types of electrical machines, it is often necessary that the motor or other machine be transferred from one source of power or current supply to another-and that this transfer be effected without connecting the two sources of power or supply together and with the shortest possible period of deenerglzation of the machine. The practice of closing a circuit breaker connecting the machine to one source of power after the breaker connecting the machine to the other source of power has opened necessitates a deenergization period at least equal to the closing time of the closing breaker.

Mechanic-almeans have been provided heretofore for so interlocking two such circuit breakers as to move one toward closed position while the other is moving toward open position so that the one will close just as the other reaches full open position.

The object of our invention, generally stated, is to provide an electrical control system for controlling the operation of a plurality of relatively movable devices which shall function to provide predetermined coordinated movements of the devices by arresting the movement of one in the event that the motion of the other is stopped or retarded a predetermined amount.

Another object of our invention is to provide an electrical control system for a pair of associated circuit breakers which shall function to open one of the breakers while closing the other breaker with a minimum period of deenergization of a device energized through the breakers.

A further object of the invention is to provide an electrical interlocking control system for a pair of circuit breakers which shall function to energize an electrically operated device from two different sources of power and which shall function to cause the circuit breakers to change the energization of the device from one source of power to the other with a minimum period of deenergization of the device while preventing connection of both of the sources of power to the device simultaneously.

Another object of the invention is to provide an electrical interlocking control system for a plurality of circuit breakers which shall be inexpensive to manufacture, install, operate, and maintain.

These and other objects and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawing in which:

Figure l is a diagrammatic view of a control .system embodying the principal features of a buses represented by conductors A, B, and C and X, Y, and Z, respectively.

The circuit breakers 2 and 4 are provided with suitable closing means in the form of solenoids 8 and I0, respectively, and mechanically trip-free operating devices actuated by tripping solenoids I2 and [4, respectively. The circuit breaker closing solenoids 8 and ID are controlled by control relays l6 and I8, respectively. The tripping solenoids I 2 and I4 and the control relays l6 and [8 are controlled by selective control switches 20 and 22 through a control system which functions to simultaneously trip the breaker 2 and energize the closing solenoid of the breaker 4.

Auxiliary control switches 24 and 26 are interconneoted by a plurality of conductors 2B, 30, 32, and 34 and are actuated by the circuit breakers 2 and 4, respectively, and function to energize the tripping solenoid [4 to prevent the breaker 4 from closing in the event that the breaker 2 fails to open, delays its opening, or sticks while opening, so that the breaker 4 will not connect the machine 6 to the power bus represented by conductors X, Y, Z while the breaker 2 is either closed to the power bus represented by the conductors A, B and C or only partially opened.

A no-voltage relay 36 is provided for automatically transferring the machine 6 from the ABC bus which is the preferred power to the XYZ bus.

The embodiment of the control system shown in Fig. 2 comprises associated potentiometers 31 and 38 connected in a bridge circuit and actuated by the motion of the circuit breakers and a sensitive polarized relay 4! responsive to a .predetermined unbalance caused by the stopping or reduced speed oi opening oi the circuit breaker 2 to actuate the tripping solenoid I4.

Considering the control system more in detail the circuit breaker 2 comprises the usual main contact elements 88, 48 and 42 mounted ior operation by a rod 44 on which there is pivotally mounted a latch bar 48. A detent 48 mounted on the latch bar 48 cooperates with a fixed detent 88 to hold the circuit breaker in the closed position as shown. A detent 82 on the latch bar 48 cooperates with a detent 84 operated by the closing solenoid 8 to move the circuit breaker to closed circuit position when the solenoid 8 is energized. The latch bar 48 is biased to latching position by a spring member 88.

The energization oi the closing solenoid 8 is controlled by the contact elements 88 and 88 oi the control relay I8 which complete a circuit ior the solenoid extending from the positive terminal oi any suitable source oi energy, as indicated, through the contact elements 88 and 88, the-conductor 82, the winding oi the solenoid 8 and the conductor 84 to the negative terminal of the source of energy. The electromagnet 88 of the relay I8 actuates the pivoted bar 88 upon which a contact element 88 is moimted in cooperative relation with a stationary contact element 88 through a pivoted bar I8 on which is pivotally mounted a. detent 12 which cooperates with a detent 14 on the bar 88.

The electromagnet 88 may be energized to close the contact elements 88 and 88 to thus energize the circuit breaker closing solenoid 8 by moving the contact element 18 oi the control switch 28 to the leit-hand position into engagement with the contact element I8. This energizing circuit extends irom the positive terminal oi the source oi electrical energy through contacts I8 and I8.

conductors 88 and 82 to winding oi the electromagnet 88 and conductors 84 and 88 to the negative terminal oi the source oi energy.

Ai-ter the circuit breaker 2 has moved to closed circuit position, a release magnet 81 oi the control relay I8 will be energized through a circuit which is completed by a front contact element 88 actuated by the circuit breaker which extends irom the positive terminal oi the source oi energy through the contact elements 18 and 18, conductor 88, contact element 88, conductor 88, the winding oi the release. magnet 81 and conductor 88 to the negative terminal of the source oi energy. The energization of the release magnet 81 will release the pivoted detent I2 irom the detent I4 and permit the contact element 88 to be disengaged irom the contact element 88 by a spring element 82, thus deenergizing the closing solenoid 8|.

When the contact element I8 oi the control switch 28 is moved to the neutral position shown in the drawing, the release magnet 81 and the electromagnet 88 will be deenergized to permit the detent 12 to be moved to engagement with the detent I4 by the spring elements 84 and 88.

The tripping solenoid I2 is energized by engagement oi the contact element I8 with a contact element 88 oi the control switch 28 through a circuit which extends irom the positive terminal oi the source oi energy through the contact elements I8 and 88, conductors 88 and I88, iront contact element I82 oi the circuit breaker 2, conductor I84, the winding oi the tripping solenoid I2 and conductors I88 and 84 to the negative terminal oi the source oi energy. This energization oi the tripping solenoid IZ will cause pivotal movement oi the bar 48 to disengage the detent 48 from the detent 88 to permit the circuit breaker contacts to move to open circuit position.

The circuit oi the tripping solenoid I2 may also be closed by the contact elemern'. I88 oi the no-voltage relay 88 through a circuit which extends irom the positive terminal oi the source oi energy through the contact element I88, conductors H8 and I88, contact element I82, conductor I84 through winding oi the tripping solenoid I2 and conductors I88 and 84 to the negative terminal oi the source oi energy, The no-voltage relay 88 is connected to be energized in the circuit oi a secondary oi a transiormer I I2 whose primary is connected to the bus conductors A and B.

The circuit breaker 4 has substantially the same arrangement oi contact elements, operating rod. latch bar. closing and tripping solenoids and control relay and the like parts oi these elements are designated by similar reierence characters in the drawing. The electromagnet 88' oi the control relay I8, however, is connected-to be energized by the movement oi the contact .element I8 oi the control switch 28 to tripping circuit position in engagement with the contact element 88. The circuit ior the electromagnet 88' extends irom the positive terminal 0! thesource oi energy to the contact elements I8 and 88, conductors 88, H4 and N8, the winding oi the electromagnet 88' and conductors H8 and I28 to the negative terminal oi the source of energy. Thus the closing solenoid I8 oi the circuit breaker 4 will be energized at the same time that the tripping solenoid I2 oi the circuit breaker 2 is energized.

When the contact element I82 oi the circuit breaker 4 moves to closed circuit position, the" release magnet 81' oi the control relay I8 will be energized through a circuit which extends irom the positive terminal oi the source oi energy to the contact elements 18 and 88, conductors 88 and I I4, contact element I82, conductor I22, the winding oi the release magnet 81 and conductor I28 to the negative terminal oi the source oi energy. The parts .0! the control relay I8 will be returned to normal position when the contact element I8 oi the control switch 28 is again moved to the neutral position indicated in the drawing.

The iunction oi controlling the herelnbeiore described circuits to actuate the tripping -solenoid I2 oi the circuit breaker 2 and the closing solenoid I8 oi the circuit breaker 4 dmultaneously may also be .periormed by moving the contact element 18' oi the control swiinh 22 to engagement with the contact element I8. thus providing a circuit extending irom the positive ter minal oi the source oi energy through the contact elements I8, I8 and conductor I24 to the conductor II4 which is in shunt circuit relation with the herelnbeiore described control circuit, which extends irom the positive terminal oi the source oi energy to the contact elements I8 and 88 and conductor 88 to the conductor H4.

The contact element I8 oi the control switch 22 may be moved to the right-hand position to engage the contact element 88' to complete an energizing circuit ior the tripping solenoid I4 oi the circuit breaker 4, extending irom the positive terminal oi the source oi energy to the contact element I8 and 88', conductor I28, contact element 88', conductor I28, the winding oi the tripr s l ienoid I4 and conductors m and u to the negative terminal of the source of energy. Thus it will be seen that the circuit breaker 2 may be tripped and theclosing solenoid of the circuit breaker 4 energized simultaneously by moving the contact element 16 of the control switch 20 to the right-hand position or by moving the contact element 16 of the control switch 22 to the left-hand position.

The auxiliary control switch 24 associated with the circuit breaker 2 comprises a movable contact element I32 actuable out of engagement with fixedelements I34, I36, I38 and I40 successively and contact element I42 as the circuit breaker 2 moves-to open circuit position. The auxiliary control switch 26 comprises a contact element I44 actuable to engage the contact element I46 and successively engage the contact elements I48, I50, I52 and I54 as the circuit breaker 4 moves toward closed circuit position. The conductors 26, 30, 32 and 34 connect the contact elements I34, I36, I38 and I40 with the contact elements I48, I50, I52 and I54, respectively. Thus as the circuit breaker 2 opens, if the opening speed is such as to open each of the contacts of the auxiliary control switch 24 before its associated contact element of the auxiliary control switch 26 is closed, there will be no connections established between the movable contact elements I 32 and I44. If, however, the speed of opening of the circuit breaker 2 is not such as to ensure opening of the circuit breaker 2 before closure of circuit breaker 4, one of the pairs of associated contacts and their connecting conductor will complete a circuit between the contact elements I32 and I44 which will energize the coil of the tripping solenoid I4 of the circuit breaker 4. This circuit extends from the positive terminal of the source of energy through the conductor I56, the contact element I 42, contact element I32, the conductor of the group of conductors 28, 30, 32 and 34 whose associated contact elements engage the movable contact members I32 and I34, the contact element I44, contact element I46, conductors I58 and I 28, the winding of the tripping solenoid I4 and conductors I30 and 64 to the negative terminal of the source of energy, thus tripping the contact elements 38, 40 and 42' of the circuit breaker 4 from the closing solenoid by disengagement of the 'detents 52' and 54 even though the closing solenoid I0 may still be energized and operating.

The embodiment of the invention shown in Fig. 2 comprises control means for the tripping solenoid I4 which may be substituted for the control switches 24 and 26 and their associated circuits in the embodiment of the invention shown in Fig. 1. Like reference characters indicate corresponding elements in the two figures oi the drawing.

In the embodiment of Fig. 2, the potentiometers 31 and 39 comprise variable resistors I60 and I62, respectively, having contact elements I64 and I66, respectively, actuable by the circuit breaker operating rods 44 and 44', respectively. The resistors I60 and I62 are connected in parallel circuit relation and are energized from any suitable source of electrical energy indicated by the positive and negative signs. The movable contact elements I64and I66 are interconnected in a circuit which extends from the contact element I64 through a conductor I68, a winding I10 of the polarized relay H and a conductor I12 to the contact element I66. Thus the potentiometers provide an equivalent Wheatstone bridge circuit in which the winding I10 of the polarized relay M is energized in accordance with the direction and degree of unbalance of the bridge.

The polarized relay 4I also has a continuously energized winding I14 and the relation of the windings I10 and I14 is such that the unbalance of the Wheatstone bridge circuit caused by the circuit breaker 2 stopping or slowing down in speed below the speed of closure of the circuit breaker 4 will cause the relay 4| to close its contact element I16. The contact element I16 controls the energizing circuit for the tripping solenoid I4 similar to the tripping solenoid circuit of the system of Fig. 1 with the contact element I16 substituted for the auxiliary switches 24 and 26 and their connecting circuits 28, 30, 32 and 34. This tripping circuit in Fig. 2 extends from the positive terminal of the source of energy through conductor I56, contact element I16, conductor I28, the winding of the tripping solenoid I4, and conductors I30 and 64' to the negative terminal of the source of energy.

Thus when the circuit breaker 2 fails to open, stops while it is opening, or fails to open at a speed having the desired relation to the speed of closure of the breaker 4, the relative movement of the contact elements I64 and I66 will be such as to unbalance the bridge circuit in such a direction as to cause the polarized relay 4| to close the tripping circuit of the breaker 4.

It is to be understood. that the principle of our invention may be readily applied to numerous other simultaneously actuable devices the illustrated embodiments of the invention being applied to circuit breakers only as an illustrative example of the application of the principles of the invention. It will be seen that we have provided an electrical interlocking control system for a pair of circuit breakers, or the like, which shall function to energize an electrically operated device from two different sources of power, which shall function to cause the circuit breakers to change the energization of the devices from one source of power to the other with a minimum period of deenergization of the device while preventing connection of both of the sources of power to the device simultaneously, and which shall function to so control the operation of any plurality of simultaneously movable devices as to prevent certain of the devices from operating at too great a speed with respect to the speed of operation of the other devices.

In compliance with the requirements of the patent statutes, we have shown and described herein the preferred embodiments of our invention. It is to be understood, however, that the invention is not limitedto the precise constructions shown and described, but is capable of modification by one skilled in the art, the embodiments herein shown and described being merely illustrative of the principles of our invention.

We claim as our invention:

1. In a control system for a pair of circuit breakers each disposed to connect an electrically operated device to a separate source of power, means for opening one of the breakers, means for operating the closing means of the other breaker, means for preventing the contacts of the said other breaker from closing, means for substantially simultaneously operating the opening means of the said one breaker and the closing means of the said other breaker, and means for operating said closure preventing means in the event that the said one breaker iails to open at a predetermined speed relative to the closing speed of the said other breaker.

2. In a control system ior a pair oi circuit breakers, means ior opening one oi the breakers,

means ior operating the closing means oi the other breaker, means ior preventing the contacts oi the said other breaker from clonng, means ior substantially simultaneously operating the opening means oi the said one breaker and the closing means oi the said other breaker, and means responsive to the relative speeds oi opening and closing oi the said one and the said other .breaker respectively ior controlling said closure preventing means.

3. In a control system ior a pair oi circuit breakers, means ior opening one oi the breakers, means ior operating the closing means oi the other breaker, means ior preventing the contacts oi the said other breaker irom closing, means ior substantially simultaneously operating the opening means oi the said one breaker and the closing means oi the said other breaker, and means responsive to the relative speeds oi opening closure oi the said one and the said other breaker respectively ior operating said closure preventing means in the event that the said one breaker iails to open at a predetermined speed relative to the closing speed oi the said other breaker.

4. In a control system ior a pair oi circuit breakers one oi which has a mechanical tripiree operating device and tripping means thereiore, means ior operating the closing means oi the said one breaker, means ior opening the other oi the breakers, means ior substantially simultaneously operating said closing means ior the said one breaker and the opening means for the said other breaker, and means responsive to the relative speeds oi closure and opening oi the said one and the said other breaker respectively ior controlling the tripping means ior the tripiree operating device oi the said one breaker.

5. In a control system ior a pair oi circuit breakers one oi which has a trip-iree operating device and tripping means therefor, means ior operating the closing means of the said one breaker, means ior opening the other oi the breakers, means ior substantially simultaneously operating said closing means ior the said one breaker and the opening means ior the said other breaker, and means ior operating the said tripping means in the event that the said other breaker fails to open at a predetermined speed relative to the closing speed oi the said one breaker.

8. In-a control system ior transferring an electrically operable device from one power supply to another without connecting the two supplies together during the transier, a pairoi circuit breakers each disposed to connect the device to a separate one oi the power supplies, means ior opening the first oi said breakers, means ior operating the closing means oi the second oi said breakers, means operable to prevent the contacts oi said second breaker from closing regardless oi the operation oi the closing means, means ior substantially simultaneously operating the opening means oi said first breaker and the closing means oi said second breaker, and means ior operating said closure preventing means in the event that said first breaker iails to open at a predetermined speed relative to the closing speed oi said second breaker.

7. In a control system ior a pair oi circuit breakers,meansioropeningafirstoneoithe breakers, means ior operating the closing means oi the second one oi the breakers, an electrically operable means ior tripping the contacts oi the second breaker iree oi the clonng means thereoi, I means ior substantially simultaneously operating the opening means oi the first breaker and the closing means oi the second breaker, and means responsive to the relative speeds oi opening and closure oi the first and second breakers respec- 1o tively ior controlling the energization oi said electrically operable trippi means.

8. In a control system ior a pair oi circuit breakers, means ior opening a first one oi the breakers. means ior operating the closing means is oi the second one oi the breakers, an electrically operable means ior tripping the contacts oi the second breaker iree oi the closing means thereoi, means ior substantially simultaneously operating the opening means oi the first breaker and the is closing means oi the second breaker, and means ior energizing said electrically operable tripping means in the event that the first breaker iails to open at a predetermined speed relative to the closing speed of the second breaker. A

9. In a control system ior a pair oi circuit breakers, means ior opening a first one oi the breakers, means ior operating the closing means oi the second one oi the breakers, means ior operating said opening and closing means subso stantially simultaneously, an electrically operable means ior tripping the contacts oi the second breaker iree oi the closing means thereoi, an energizing circuit ior said electrically operable tripping means including cooperating contact a means operable by the opening oi the first breaker and the closing oi the second breaker ior energizing said tripping means in the event that the first breaker fails to open at a predetermined speed relative to the closing speed oi the second breaker.

10. In a control system ior a pair oi circuit breakers, means ior opening a first one oi the breakers, means ior operating the closing means oi the second one of the breakers, means ior operating said opening and closing means substantially simultaneously, an electrically operable means ior tripping the contacts of the second breaker iree oi the closing means thereoi, and an energizing circuit ior said electrically operable tripping means including first contact means actuated to open position by a predetermined movement oi the first breaker toward open position and second contact means actuated to closed position by a predetermined movement of the 55 second breaker toward closed position.

11. In a control system ior a pair oi circuit breakers, means ior opening a first one oi the breakers, means ior operating the closing means oi the second one oi the breakers, means ior so operating said opening and closing means substantially simultaneously, an electrically operable means ior tripping the contacts oi the second breaker iree oi the closing means thereoi, and an energizing circuit ior said electrically operable tripping means including a first control means, a second control means, and means whereby said first and second breakers actuate said first and second control means respectively, said first control means comprising a plurality 7 oi fixed contact elements and a contact element movable by said first circuit breaker so disposed with respect to said fixed contact elements so to move to open circuit position with respect to successive ones oi said fixed contact elements as 76 said first circuit breaker moves to open circuit position, said second control means comprising a plurality of fixed contact elements and a contact element movable by said second circuit breaker so disposed with respect to said fixed contact elements as to move to closed circuit position with respect to successive ones of said fixed contact elements as the second circuit breaker moves to closed circuit position, circuit means connecting successive ones of said fixed contact elements of said first control means with successive ones of said fixed contact elements of said second control means, whereby the energizing circuit for said electrically operable tripping means will be completed in the event that the opening movement of said first circuit breaker fails to move the successive contact elements of said first control means to open circuit position before the closing movement of said second circuit breaker moves the corresponding successive contact elements of said second control means to closed circuit position.

12. In a control system for a pair of circuit breakers, means for opening a first one of the breakers, means for operating the closing means of the second one of the breakers, means for operating said opening and closing means substantially simultaneously, an electrically operable means for tripping the contacts of the second breaker free of the closing means thereof, and an energizing circuit for said electrically operable tripping means including first and second control means operable by said first and second circuit breakers, respectively, a plurality of circuits extending between said first and second control means, means whereby the first control means opens successive ones of said circuits as it is operated by said first circuit breaker as it moves from closed to open position, means where- 40 by the second control means closes successive ones of said circuits in the order. of opening of said circuits by said first control means as it is operated by said second circuit breaker as it moves from open to closed position, whereby the energizing circuit for said electrically operable tripping means will be completed in the event that the opening movement of the first breaker fails to open the successive circuits before the closing movement of the second breaker closes the successive circuits.

13. In a control system fora pair of circuit breakers, means for opening a first one of the breakers, means 'for operating the closing means of the second one of the breakers, means for operating said opening and closing means substantially simultaneously, an electrically operable means for tripping the contacts of the second breaker free of the closing means thereof, and an energizing circuit for said electrically operable tripping means including first and second control means operable by said first and second circuit breakers respectively, a plurality of circuits extending between said first and second control means, means whereby one of said control means opens successive ones of said circuits as it is operated by said its associated breaker, and means whereby the other control means closes successive-ones of said circuits in the order of opening by said one control means as it is operated by its associated circuit breaker, whereby the energizing circuit for said electrically operable tripping means will be completed in the event that the one control means fails to open the successive circuits before the other control means closes the successive circuits.

14. In a control system for a moving device, in combination, means for arresting the motion of the moving device, and means responsive to the relative motion of the device with respect to another device for controlling the said motion. arresting means.

15. In a system for controlling the motion of a moving device, means for arresting the motion of the device, and means for automatically actuating said motion arresting means in the event that the motion of a second moving device is stopped before it reaches a predetermined point in its motion.

16. In a control system for a pair of movable devices, means for moving one of the devices, means for moving the other of the devices, means for arresting the motion of the said other device, and means for automatically actuating said motion arresting means in the event that the. motion of the said one device is arrested or decreased in speed a predetermined amount.

1'7. In a control system for a pair of movable devices, means for moving one of the devices, means for moving the other of the devices, means for arresting the motion of the said other device, a potentiometer device actuated by the motion of said one device, a potentiometer device actuated by the motion of the said other device, and means responsive to the relative actuations of said potentiometers for actuating said motion arresting means, whereby the motion of the said second device will be arrested in the event that the motion of the said first device is stopped or fails to maintain a predetermined rate relative to the motion of the said second device.

18. In a control system for a pair of circuit breakers, means for opening a first one of the breakers, means for operating the closing means of the second one of the breakers, means for operating said opening and closing means substantially simultaneously, an electrically operable means for tripping the contacts of the second breaker free of the closing means thereof, a potentiometer operable by the opening motion of the said first breaker, a potentiometer operable by the closing motion of the said second breaker, and means responsive to the relative actuations of said potentiometers for energizing said tripping means, whereby the contacts of the said second breaker will be prevented from closing in the event that the motion of the said first breaker is stopped or fails to maintain a predetermined rate relative to the motion of the said second breaker.

19. In a control system for a pair of movable devices, means for moving one of the devices, means for moving the other of the devices, means for arresting the motion of the said other device, variable impedance means actuable by the motions of said movable devices, and means responsive to the relative actuations of said variable irnpedance means for actuating said motion arresting means, whereby the motion of the said second device will be arrested in the event that the motion of the said first device is stopped or fails to maintain a predetermined rate relative to the motion of the said second device.

ALFRED J A. PETERSON. LLOYD W. DYER. CHARLES P. WEST. 

